BACTERIA
99% of bacteria is helpful and less than 1% is harmful and causes disease. Bacteria can be helpful in the digestion process, medical and pesticide use, and in the environment but it can also cause disease and spoil foods. Bacteria is a unicellular, microscopic prokaryote that belongs to the Kingdom Manera and can be killed by antibiotics, only if the bacteria is not resistant. Alexander Fleming discovered penicillium around the start of World War II which allowed sick soldiers and civialians to kill off common sicknesses. Bacteria was the first form of life on Earth and is now the most numberous organism in the world. There is more bacteria in your body than human cells and it produces more than half of the oxygen found in the atmosphere. There are also more microbes on your body than humans on the planet, a square inch can be home to more than half a million microbes. Bacterial infections are usually localized at a single point in the body and comes in many different shapes and sizes. The three basic shapes are coccus (sphere, ex: streptococcus - strep throat and athrax which causes death due to oxygen depletion), bacillius (rods, ex: e. coli which can be caused by intestinal infection caused by ingestion of contaminated food or water), and spirillum (spiral, ex: chlorea). Unlike a virus, bacteria can reproduce on its own, without a host, through the process of binary fission. A single healthy bacterium could reproduce into a colony of more than 200 million in about seven hours. There are three different types of relationships between bacteria and oxygen. Obligate aerobe (requires oxygen), obligate anaerobe (complete absense of oxygen), and facultative anaerobe (can survive with or without oxygen).
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Binary Fission